Tri3 Assessment Notes

When asked to find the area or perimeter of a PART of a geometric figure, there are two ways to think about the problem.
For example, let's say that you have a rectangle. The area is length time width or 9 x 3 = 27 square units.

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Another version of the problem could be to find the area of the rectangle if it is missing 1/3 or the shape.
There are two ways to solve this problem:
  1. The first is to take 2/3 of the overall area or 2/3 * 27 = 18 square units
  2. Another way is to take the overall area and substract the missing one-third or 27 - (1/3 * 27) = 27 - 9 = 18 square units
important: note that you are subtracting one-third of the area and not just 1/3; you should not do 27 - 1/3 !!!